The present invention relates to an internal combustion engine of a motorcycle, and more particularly, to the layout of an oil filter and its associated members.
According to a conventional motorcycle engine, the oil filter is provided at a position in front of the crank case. However, since the exhaust pipe is also disposed in front of the crank case, it is difficult to clean the casing of the oil filter to remove the mud splashed from the front wheel. Further, since the oil filter casing protrudes toward the front wheel, the outer appearance of the resultant motorcycle is degraded. Furthermore, the oil filter casing may be subjected to heat, since it is positioned adjacent to the cylinders of the engine and the exhaust pipe, so that it is necessary to often carry out maintenance work. Moreover, the oil pump is positioned at a position behind the center axis of the crankshaft. Therefore, the oil passage becomes long when the oil filter casing is disposed in front of the crank case.